Fallen snowflake--a rare sight.

"Snow crystals," Ukichiro Nakaya wrote in "may be called letters sent from heaven." The Japanese physicist spent his life studying snowflakes, eventually becoming the first to create an artificial snow crystal in the laboratory.

Snow Flake ~ by ViaMoi (see more on flikr)

Alexey Kljatov is a Moscow-based photographer who takes a special interest in shooting snowflakes. He does a lot of work in post-production, adding colour or even working with multiple pictures to create a single composite image of a flake.